This invention relates to liquid transfer assemblies.
Previous methods of administering drugs to patients by means of a syringe involves fitting a needle to the syringe, breaking the neck off a glass drug ampoule, inserting the needle into the ampoule, drawing up the drug into the syringe and then injecting the drug in the usual way, after having evacuated air from the syringe.
There are many disadvantages with such methods which arise from the use of a glass ampoule to contain the drug.
For example, breaking the neck of the ampoule can result in glass shards being produced. These can in some case contaminate the contents of the ampoule and may be drawn up into the syringe. The shards and the broken parts of the ampoule also present a hazard to the clinician administering the drug by increasing the risk of cutting the skin and allowing contamination of or by the clinician. The act of inserting a sharply pointed needle into the narrow severed neck of the ampoule also presents the risk that the user will be pricked by the needle if it is not correctly inserted. Holding the drug ampoule and the syringe barrel while withdrawing the syringe plunger requires some manual dexterity and is difficult where the clinician's hands are wet or, in an emergency.
The glass ampoules require special disposal facilities after use, to avoid injury and contact with unused contents of the ampoules. Packaging and transport of the ampoules must be such that they will not be damaged. This can lead to bulky and expensive packaging.
The ampoules are only suitable for administration of a single dose, leading to wastage and complications where doses of different volumes need to be given. There is also the disadvantage that the drug must be transferred to the syringe immediately after having broken off the ampoule neck if the drug is of a kind that is affected by contact with air.